19. The use of a space for commercial purposes or the exercise of a profession in a residence is allowed in the following circumstances:
(1) the user lives in the residence;
(2) the activity is performed entirely in a space of the residence reserved for that purpose and does not involve the use of outdoor space;
(3) the space used occupies 40% or less of the total area of the floor of the residence;
(4) the activity does not involve the accommodation of clients;
(5) the use of the immovable for that purpose will not subject the installation of a new breeding unit or the increase of the activities of an existing breeding unit to a separation distance requirement related to odours more stringent than the requirement for a dwelling.
Where a number of commercial or professional activities are performed in the residence, the maximum space used provided for in subparagraph 3 of the first paragraph applies to all of those activities.